Electrolysis of water is the decomposition of water (H2O) into oxygen (O2) and hydrogen gas (H2) due to an electric current being passed through the water.
Conventional alkaline water electrolyzers operate by placing two electrodes in a bath of liquid electrolyte, such as an aqueous solution of potassium hydroxide (KOH). The electrodes, one being an anode and the other being a cathode, are separated from each other by a separation membrane, or cell membrane, that selectively allows passage of ions but not gas through it. When a voltage is applied across the electrodes, current flows through the electrolyte between the electrodes. Hydrogen gas is produced at the cathode and oxygen gas is produced at the anode. The separation membrane keeps the hydrogen and oxygen gases separated as the generated gas bubbles rise through the liquid electrolyte. The efficiency of such electrolyzers is mainly limited by the reaction evolving oxygen gas at the anode. Also, the high-pressure limit of these electrolyzers may be adversely affected by diffusion of hydrogen gas through the separation membrane and into the oxygen compartment, where it combines with oxygen in an exothermic reaction, wherein such generated heat may adversely affect one or more elastomeric components associated with the electrolyzer, including elastomeric hoses coupled to the gas outlets, which ultimately may lead to electrolyzer failure.